Hi Oleg,

do you mean a backport to 3.3?

gael

On Wed, Mar 20, 2019 at 3:51 PM Oleg Shirokobrod <[email protected]>
wrote:

> Hi Gael,
>
> You finally modified PolynomialSolver.h code for finding roots of
> polynomial with complex coefficients and wrote unit test. This enhancement
> is very important for signal processing application. This modification of
> PolynomialSolver.h and Companion.h are rather trivial and localized. So it
> is safe to modify existing code. Would it be possible to include them to
> the next release?
>
> Best regards,
>
> Oleg
>
>
> On Wed, Nov 23, 2016 at 5:09 PM Gael Guennebaud <[email protected]>
> wrote:
>
>> Done:
>>
>> https://bitbucket.org/eigen/eigen/commits/3842186ae759/
>> https://bitbucket.org/eigen/eigen/commits/eff1bfef71a2/
>> https://bitbucket.org/eigen/eigen/commits/df6c723906fc/
>>
>> gael
>>
>> On Wed, Nov 23, 2016 at 3:39 PM, Gael Guennebaud <
>> [email protected]> wrote:
>>
>>> Sorry for late reply, but thanks for the patches.
>>>
>>> Regarding the eigen-solver choice issue, it's possible to automatically
>>> use the right one based on NumTraits<Scalar>::IsComplex and conditional<>.
>>>
>>> We would also need to extended the unit test to cover complexes.
>>>
>>> gael
>>>
>>> On Tue, Nov 8, 2016 at 3:41 PM, Oleg Shirokobrod <
>>> [email protected]> wrote:
>>>
>>>> Dear list,
>>>>
>>>> Polynomial solver currently finds roots only for real polynomial
>>>> coefficients. Having Eigen::ComplexEigenSolver lets Polynomial module to
>>>> compute roots for complex polynomial coefficients. I have made necessary
>>>> modifications. I have attached corresponding patch files. Unfortunately
>>>> module cannot deduce type of the solver from partial specialization of
>>>> corresponding matrix type, such that
>>>>
>>>> template<typename RealScalar> class EigenSolver {};
>>>>
>>>> template<typenameRealScalar> class
>>>> EigenSolver<Eigen::Matrix<RealScalar,_Deg,_Deg> > {// EigenSolver };
>>>>
>>>> template<typename  RealScalar> class
>>>> EigenSolver<Eigen::Matrix<std::complex<RealScalar>,_Deg,_Deg > > {
>>>> //ComplexEigenSolver};
>>>>
>>>> So I have to add additional template parameter EigenSolverType with
>>>> default value for real coefficients:
>>>>
>>>> template< typename _Scalar, int _Deg , typename EigenSolverType =
>>>> EigenSolver<Matrix<_Scalar,_Deg,_Deg> > >
>>>> class PolynomialSolver : public PolynomialSolverBase<_Scalar,_Deg>{};
>>>>
>>>> I have to replace in number of places in the file Companion.h (mainly
>>>> in functions balanced() and balance()) Scalar with RealScalar, where
>>>> variables are really real.
>>>>
>>>> With this code I have run test against Matlab and it gave similar
>>>> results.
>>>>
>>>> Test
>>>> VectorXcd roots = VectorXcd::Random(4);
>>>> VectorXcd polynomialCoefficients;
>>>> roots_to_monicPolynomial(roots, polynomialCoefficients);
>>>>
>>>> cout << "roots : " << endl;
>>>> cout << setprecision(14) << roots << endl;
>>>> cout << "polynomialCoefficients : " << endl;
>>>> cout << setprecision(14)  << polynomialCoefficients << endl;
>>>>
>>>> PolynomialSolver<std::complex<double>, Dynamic,
>>>> ComplexEigenSolver<MatrixXcd> > psolve(polynomialCoefficients);
>>>>
>>>> VectorXcd computedRoots = psolve.roots();
>>>>
>>>> cout << "computedRoots : " << endl;
>>>> cout << setprecision(14) << computedRoots << endl;
>>>>
>>>> for(int index = 0; index < computedRoots.size(); ++index)
>>>> {
>>>>     cout << setprecision(14) << "polynom at  computedRoots * 1.0 e-11:
>>>> " << poly_eval(polynomialCoefficients, computedRoots(index))*1.0e11 << 
>>>> endl;
>>>> }
>>>>
>>>> Output:
>>>> roots :
>>>> (0.12717062898648,-0.99749748222297)
>>>> (0.61748100222785,-0.61339152195807)
>>>> (-0.04025391399884,0.17001861629078)
>>>> (0.79192480239265,-0.29941709646901)
>>>>
>>>> polynomialCoefficients :
>>>> (0.091649023983597,-0.091441416775918)
>>>> (0.24020598856634,0.37401934653925)
>>>> (-0.16301627948124,-1.8544616197629)
>>>> (-1.4963225196081,1.7402874843593)
>>>> (1,0)
>>>>
>>>> computedRoots :
>>>> (-0.04025391399884,0.17001861629078)
>>>> (0.79192480239265,-0.29941709646901)
>>>> (0.61748100222785,-0.61339152195807)
>>>> (0.12717062898648,-0.99749748222297)
>>>>
>>>> polynom at  computedRoots * 1.0 e-11:
>>>> (8.3266726846887e-006,-1.2490009027033e-005)
>>>> polynom at  computedRoots * 1.0 e-11:
>>>> (4.7184478546569e-005,-1.6653345369377e-005)
>>>> polynom at  computedRoots * 1.0 e-11:
>>>> (2.2204460492503e-005,-1.3877787807814e-005)
>>>> polynom at  computedRoots * 1.0 e-11:
>>>> (1.5163809063462e-005,-2.7286889655471e-005)
>>>>
>>>> Matlab for the same coefficients gives following roots (remember that
>>>> matlab array of coefficients and Eigen one are reversed to each other)
>>>>
>>>> computedRoots :
>>>> 0.127170628986480 - 0.997497482222969i
>>>> 0.617481002227849 - 0.613391521958071i
>>>> 0.791924802392650 - 0.299417096469009i
>>>> -0.040253913998840 + 0.170018616290780i
>>>>
>>>> Best regards,
>>>>
>>>> Oleg Shirokobrod
>>>>
>>>>
>>>>
>>>
>>

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